Endoplasmic Reticulum Overview

These flashcards cover the structure, function, and clinical correlations related to the Endoplasmic Reticulum (ER), including its types, specific cellular examples, and associated diseases.

What is the main structural difference between Rough ER and Smooth ER?

Rough ER is studded with ribosomes, while Smooth ER lacks ribosomes.

What is the role of ribosomes in Rough Endoplasmic Reticulum (RER)?

Ribosomes attached to the cytosolic surface of RER are involved in synthesizing membrane-bound, secretory, and lysosomal proteins.

What process occurs co-translationally in the RER?

Protein translation occurs co-translationally into the ER lumen via translocons.

What are COP II-coated vesicles responsible for?

They carry proteins from the Rough ER to the Golgi apparatus for further processing.

Identify one cellular example of RER function.

Pancreatic exocrine cells, which synthesize digestive enzymes.

What is one function of the Smooth Endoplasmic Reticulum (SER)?

Lipid synthesis, including phospholipids, cholesterol, and steroid hormones.

How does the SER assist in detoxification?

By containing cytochrome P450 monooxygenases (CYP450) to convert hydrophobic toxins into hydrophilic metabolites for excretion.

What enzyme in the SER is crucial for gluconeogenesis?

Glucose-6-phosphatase converts glucose-6-phosphate into glucose for export.

Which specialized SER is found in muscle cells?

Sarcoplasmic reticulum (SR), which stores calcium for muscle contraction.

What process leads to the activation of the Unfolded Protein Response (UPR)?

Accumulation of misfolded proteins in the endoplasmic reticulum.

What are the consequences of ER dysfunction in terms of diseases?

It contributes to metabolic, hepatic, and neurodegenerative diseases.

What role do folding chaperones like BiP, Calnexin, and Calreticulin play in the ER?

They assist in the folding of proteins and the formation of disulfide bonds.